dominoes

3 Articles

When life gives you lemons, you make lemonade. At least that’s what the [Sprice Machines] thought when they decided to turn a house into the set of a 9-minute long Rube Goldberg machine to make lemonade. (Video embedded below.) The complex chain reactions runs across multiple rooms, using everyday objects like brooms and even a vibrating smartphone to transfer energy across the complex contraption.

While the team professionally builds Rube Goldberg machines for clients, the Lemonade Machine looks surprisingly organic, like something a family might decide to do for fun over a long weekend (although there area few moments that make you question just how they were able to perfectly time every sequence in the chain reaction). Even though the actual lemonade making only takes up a small fraction of the machine, watching marble runs, weights dashing across a clothesline, and random household items repurposed into energy transfer mechanisms is really entertaining.

[Fede.tft] wrote in to tell us about some work he’s been doing to save battery life for LED dominoes. He originally got the idea after reading this post about the electronic gaming pieces. That project was aimed at the 555 timer contest and therefore, used a 555 timer. [Fede.tft] calculates the battery life for the CR2302 battery in the 555 circuit at no more than about 80 days. That’s if you never use them and the LEDs are never illuminated. It makes sense to remove the batteries from the device when not in use, but a redesign to increase efficiency is definitely worth the effort.

This rendition does away with the 555 chip in favor of a CMOS chip. By building a circuit around four NAND gates of a CD4011 chip, the standby lifetime of the battery is calculated to increase to about 4.5 years. Not bad! Add to this the fact that replacing the 555 timer didn’t increase the component count, the price for the chip is similar to the 555, and you didn’t need to resort to a microcontroller. Yep, we like it.

Toppling dominoes is great fun for about 30 seconds at a time, when you are not busy setting them up for another run. [Randy] thought it was about time they got an electronic makeover to allow for constant, immediate gratification. Armed with a few simple electronic components, he has created Le Dominoux.

These LED-based electronic dominoes are actually quite simple to build. Each basic Le Dominoux is constructed on a small square of protoboard and consists of either a photo cell or phototransistor, a 555 timer, and an LED, all powered by a coin cell battery. The 555 timer, which is configured as a one-shot, is triggered when the photosensitive component on the back side of the domino is exposed to a bright enough light. The LED on the front end of the domino is then illuminated one time. This process is the electronic equivalent of a single domino toppling over.

He has constructed several variants of the Le Dominoux to act as flashing triggers, for outputting sound, as well as for turning tight corners. These variants allow the dominoes to be configured in many different ways, creating self-sustaining light shows. If anyone is looking for a fun project to introduce kids to electronics, this would definitely be it. Stick around to see a video of Le Dominoux in action – we bet you can’t stop watching it.

This is of course [Randy’s] entry in the 555 Design Contest, which ends tonight at midnight EST.